In only one doubtful passage is the north-east monsoon alluded to.

The storm so vividly described in the Rig Veda is the south-west monsoon which is felt in the northern Punj[=a]b.

The north-east monsoon is felt to the southeast of the Punj[=a]b, possibly another indication of geographical extension, withal within the limits of the Rig Veda itself.
The seat of culture shifts in the Brahmanic period, which follows that of the Vedic poems, and is found partly in the 'holy land' of the west, and partly in the east (Beh[=a]r, Tirhut).[23] The literature of this period comes from Aryans that have passed out of the Punj[=a]b.
Probably, as we have said, settlements were left all along the line of progress.

Even before the wider knowledge of the post-Alexandrine imperial age (at which time there was a north-western military retrogression), and, from the Vedic point of view, as late as the end of the Brahmanic period, in the time of the Upanishads, the northwest seems still to have been familiarly known.[24] * * * * * FOOTNOTES: [Footnote 1: We take this opportunity of stating that by the religions of the Aryan Hindus we mean the religions of a people who, undoubtedly, were full-blooded Aryans at first, however much their blood may have been diluted later by un-Aryan admixture.

Till the time of Buddhism the religious literature is fairly Aryan.